Acrylonitrile-butadiene-styrene (hereinafter referred to as ABS) resin has rigidity and chemical resistance, which are properties of acrylonitrile, and processability, mechanical strength, and aesthetics, which are properties of butadiene and styrene, thereby being applied to various products such as automotive products, electrical and electronic products, and office equipment.
In general, ABS resin or resins similar thereto are applied using a method of increasing an addition amount of a heat stabilizer to improve thermal stability and surface gloss, a method of removing a residual monomer by stripping an ABS copolymer latex, and a method of additionally adding water during coagulation and dehydration to minimize the residual content of an emulsifier, etc.
However, when an excessive amount of heat stabilizer is added, problems, such as deterioration in mechanical properties of a resin, may occur. In addition, when a stripping process is applied, a residual monomer can be usefully removed, but a separate process should be additionally performed. Accordingly, cost and time increase, and thus, productivity is decreased. Although the stripping process is applied, there are limitations in removing organic substances having a high volatilization temperature. In addition, when a residual emulsifier is removed by additionally adding water during coagulation and dehydration, the amount of wastewater increases, and a large amount of gas is generated from a residual emulsifier remaining also after a removal process during processing, whereby surface gloss is decreased.